The
Arctic was literally off-the-charts warm last month, as we’ll see.
It’s no surprise, then, that Arctic sea ice set a record for the
lowest maximum extent.

First,
the University of Alabama at Huntsville (UAH) data shows that in
March the lower troposphere (the lowest part of the atmosphere) was a
remarkable 1.3°F (0.73°C) above the historical (1981-2010) average,
a baseline that is already some 0.8°F (0.45°C) hotter than
pre-industrial levels.

Higher
highs and higher lows — the warming trend is quite clear in the
satellite data. As the UAH’s Roy Spencer and John Christy — both
leading deniers — have
reported,
the UAH data shows a “global climate trend since Nov. 16, 1978 [of]
+0.12 C [0.22F] per decade.”

But
wait, how is it that Ted
Cruz
and other climate science deniers keep claiming there hasn’t been
any warming in the satellite record since 1998? The short answer is
they’ve been ignoring all of the reliable sources that show
warming, but have focused on the one satellite record that even
Spencer
and Christy
knew was in error. Now that this error has been corrected in the
peer-reviewed literature, as we
reported,
there aren’t any more datasets that don’t show warming.

“Record-Shattering
February Warmth Bakes Alaska, Arctic 18°F Above Normal,” was the
Climate
Progress story
last month when NASA released its February temperature data. How warm
was the Arctic in March? Off the chats.

Look
at what the heat did: It kept Arctic sea ice growth almost flat for
over a month during a time when sea ice extent normally soars to its
annual maximum.

The result, as the National Snow and Ice Data Center
(NSIDC) reported
last week,
was the lowest winter maximum on record.

“I’ve
never seen such a warm, crazy winter in the Arctic,” reported
NSIDC director Mark Serreze. “The heat was relentless.”

The
NSIDC has a metric for how warm (or cold) the Arctic has been called
“freezing degree days” (FDDs). Their website
explains:

The
relationship between thermodynamics and sea ice thickness can be
thought of most simply in terms of freezing
degree days (FDD),
which is essentially a measure of how cold it has been for how long.
The cumulative FDD is simply daily degrees below freezing summed over
the total number of days the temperature was below freezing.

NSIDC
scientist Andrew Slater has an amazing chart on his
website
of freezing degree days in 2016 compared to other years at 80 degrees
north latitude:

In
the Arctic, 2016 (bottom red line) has been anomalously warm.

“This
year’s trend line is not only way outside of the percentile zones,”
Neven Acropolis notes
at his must-read Arctic sea ice blog, “it’s falling off the
chart.” This unusual warmth is a key reason Arctic sea ice extent
just saw its lowest maximum on record.

It
bears repeating that recent research
finds that rapid Arctic warming, driven in part by sea
ice loss,
is already worsening extreme weather. Also, the permafrost contains
twice as much carbon as the atmosphere, and as it defrosts, it
releases that carbon in the form of either CO2 or an even more potent
heat-trapping greenhouse gas, methane (CH4). Thus as Arctic warming
speeds up, it boosts global greenhouse gas levels, which leads to
even more warming of the Arctic and so on.

That’s
why we must pay attention to what happens in the Arctic — and do
everything we can to stop global warming ASAP.